Enter! The Micro-Wyrm!
Arguably not even an animal, the Micro-Wyrm is a colony of symbiotic single celled organisms that work as a single unit. It is free floating, and fees by both photo-synthesizing using its two chlorophyll producing "wing" cells, and by absorbing nutrients from the water using its pale blue "tail" cell. Its "head" cell filters out and expels toxins while metabolizing nutrients absorbed by the tail cell into chemical compounds vital for the rest of the colonies survival. It is limp, and incapable of locomotion.
